Association Analysis of Candidate Genes of Host Responses to PRRS Virus Infection

Genetically improve the host resistance to the pathogen PRRSV is a potential strategy to control or lower the impact of the PRRS to the pig industry. The Effect of polymorphisms in GBP1, Mx1 and CD163 genes on pig resistance to PRRSV infection was evaluated. The results showed that pigs with the AG genotype for the GBP1 gene exhibited a significantly higher average daily weight gain (ADWG) and lower average viremia, as did pigs with the CC genotype for the CD163 gene. However, pigs with a single 11-bp deletion or insertion in the Mx1 gene did not show significant differences in either weight gain or viremia. The potential causative mutation in the exon2 of the porcine GBP1 gene was explored by a deep sequencing and a test of the associations between the variants and the host immune response to PRRSV infection. A total of eight SNPs, including five missense mutations, was observed in the exon2 region. These eight SNPs were separated into three haplotype blocks (B1, B2 and B3) by total linkage disequilibrium. Based on these results, we concluded that GBP1 is most significantly associated with resistance against PRRSV infection.